Field of the Invention
The present disclosure relates to an electrochromic device and an electrochromic dimming device.
Description of the Related Art
Electrochromism is a phenomenon where redox reactions are performed reversibly to reversibly change a color. Devices utilizing the electrochromism are electrochromic devices. Various researches have been performed on the electrochromic devices to develop applications derived from characteristics of the electrochromism.
The electrochromic device typically performs redox reactions with a structure where an electrochromic material is formed between two facing electrodes, and the space between the electrodes is filled with an electrolyte layer capable of conducting ions. Since the electrochromism is an electrochemical phenomenon, a performance (e.g., ion conductivity) of the electrolyte layer affects a response speed or a memory effect of coloring. Fast responses tend to be obtained when the electrolyte layer is a liquid state where an electrolyte is dissolved in a solvent, but an improvement of the electrolyte layer through solidification or gelation has been considered in view of strength of an element and reliability.
When the electrochromic device is used as dimming glass or used for display, at least one side of the electrochromic device needs to be sealed with a transparent material, such as glass and plastic. Therefore, it is difficult to completely seal an electrolyte in with a metal etc. Accordingly, leakage or evaporation of the electrolyte layer is a significant problem. As a method for solving the problem, use of a polymer solid electrolyte is proposed. Examples of the polymer solid electrolyte include solid liquids between a matrix polymer including an oxyethylene chain or an oxypropylene chain and inorganic particles. The above-mentioned solid liquids are completely solids, and excel in processability, but have a problem that conductivity is low.
In order to improve conductivity of the polymer solid electrolyte, for example, proposed are a method where a polymer is dissolved in an organic electrolytic solution to form into a semi-solid, and a method where liquid monomers, to which an electrolyte is added, are allowed to perform a polymerization reaction to form a cross-linked polymer including the electrolyte.
Meanwhile, the electrochromic device includes extraction electrodes configured to connect two electrodes to a power source device in order to apply voltage between the two electrode sandwiching an electrochromic material. It is often a case that two extraction electrodes are bonded to sift the patterns of the two electrodes to create a region where the two electrodes do not face each other.
In case of a transmission electrochromic device, transparent electrodes need to be used as the two electrodes. For example, SnO2, In2O3, ITO, ZnO, etc. are known as a material of the transparent electrode, but the above-listed materials have high resistance, which causes a problem that a response of an electrochromic reaction is slow.
In order to improve the response, for example, proposed is an electrochromic element, in which a third electrode layer having lower resistance than an upper electrode layer is disposed above the upper electrode layer via a conductive resin layer, and extraction of the upper electrode layer is performed from the third electrode layer (see, for example, Japanese Patent No. 2512880). Moreover, proposed is an electrochromic device, in which a metal grid electrode is formed in a transparent conductive film (see, for example, Japanese Unexamined Patent Application Publication No. 2010-014917).